Chemical ozone loss in the Arctic and Antarctic stratosphere between 1992 and 2005 (original) (raw)
Related papers
The potential for ozone depletion in the Arctic polar stratosphere
Science, 1991
The nature of the Arctic polar stratosphere is observed to be similar in many respects to that of the Antarctic polar stratosphere, where an ozone hole has been identified. Most of the available chlorine (HCl and ClONO,) was converted by reactions on polar stratospheric clouds to reactive ClO and C1202 throughout the Arctic polar vortex before midwinter. Reactive nitrogen was converted to HNO,, and some, with spatial inhomogeneity, fell out of the stratosphere. These chemical changes ensured characteristic ozone losses of 10 to 15% at altitudes inside the polar vortex where polar stratospheric clouds had occurred. These local losses can translate into 5 to 8% losses in the vertical column abundance of ozone. As the amount of stratospheric chlorine inevitably increases by 50% over the next two decades, ozone losses recognizable as an ozone hole may well appear.
Chemical depletion of Arctic ozone in winter 1999/2000
Journal of Geophysical Research, 2002
1] During Arctic winters with a cold, stable stratospheric circulation, reactions on the surface of polar stratospheric clouds (PSCs) lead to elevated abundances of chlorine monoxide (ClO) that, in the presence of sunlight, destroy ozone. Here we show that PSCs were more widespread during the 1999/2000 Arctic winter than for any other Arctic winter in the past two decades. We have used three fundamentally different approaches to derive the degree of chemical ozone loss from ozonesonde, balloon, aircraft, and satellite instruments. We show that the ozone losses derived from these different instruments and approaches agree very well, resulting in a high level of confidence in the results. Chemical processes led to a 70% reduction of ozone for a region $1 km thick of the lower stratosphere, the largest degree of local loss ever reported for the Arctic. The Match analysis of ozonesonde data shows that the accumulated chemical loss of ozone inside the Arctic vortex totaled 117 ± 14 Dobson units (DU) by the end of winter. This loss, combined with dynamical redistribution of air parcels, resulted in a 88 ± 13 DU reduction in total column ozone compared to the amount that would have been present in the JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. D20, 8276,
Atmospheric Chemistry and Physics, 2010
Most of the ozone loss (60-75%) at this level results from nitrogen catalytic cycles rather than halogen cycles. At both 475 and 675 K levels the simulated ozone and ozone loss evolution inside the vortex is in reasonably good agreement with the MLS observations. The ozone partial column loss in 350-850 K deduced from the model calculations at the MLS sampling locations inside the polar vortex ranges between 43 DU in 2005/2006 and 109 DU in 2004/2005, while those derived from the MLS observations range between 26 DU and 115 DU for the same winters. The partial column ozone depletion derived in that vertical range is larger than that estimated in 350-550 K by 19±7 DU on average, mainly due to NO x chemistry. The column ozone loss estimates from both Mimosa-Chim and MLS in 350-850 K are generally in good agreement with those derived from ground-based ultravioletvisible spectrometer total ozone observations for the respective winters, except in 2010.
Chemical Loss of Ozone in the Arctic Polar Vortex in the Winter of 1991-1992
Science, 1993
The H, O trend is estimated by calculating the difference between the average H20 with the H, O residual estimated in K. Kelly et a/. [Geophys. Res. Lett. 17, 465 (1989)], and scaling with the CH, trend. The H20 difference is a result of CH, oxidation in the stratosphere. 17. The HNO, trend is estimated by assuming that the NO, trend is the same as the N, O trend (0 2%) and using the scaling of NO, (10). 18. Projected injections of NO, and H, O are taken from scenario F in M. Prather et a/. [NASA Ref. Publ. 1272 (1992)l. In this report, NO is estimated to increase 4 ppbv and H, O will rncrease by about 1 ppmv, for an emission index of 15 and a Mach number 3.2. 19. T. Peter et a/. [Geophys. Res. Lett. 18, 1465 (1991)l calculated a doubling of the PSC probability for future fleets of stratospheric aircraft (a 1.7 K increase in the 50-hPa NAT saturation temperature using a two-dimensional chemistry model). 20. We thank all the partic~pants in the AASE II mission.
Ozone depletion in the late winter lower Arctic stratosphere: Observations and model results
Journal of Geophysical Research, 1997
Ozone loss rates in the lowermost part of the Arctic stratosphere (at potential temperature levels <-375 K) in the period January and February 1993 are calculated using a chemistry-trajectory model and 30-day back trajectories. The results were compared with observations carried out during the first Stratosphere Troposphere Experiment by Aircraft Measurements (STREAM) in February 1993 in the Arctic lower stratosphere. Relatively low N20 and low 03 concentrations were measured during STREAM, and 03 loss rates of 8.0 (_+3.6) ppbv d -• were calculated from O3-N20 STREAM data in the vortex area. The average 03 loss rate calculated by the model is 8.6 ppbv d -• (1.3% d-•), in agreement with observations. However, the calculated 03 loss rate decreases to the lower value of the observed loss rates when taking into account N20-Cly interrelations from different studies.
Geophysical Research Letters, 2001
Lower stratospheric in situ observations are used to quantify both the accumulated ozone loss and the ozone chemical loss rates in the Arctic polar vortex during the 1999-2000 winter. Multiple long-lived trace gas correlations are used to identify parcels in the inner Arctic vortex whose chemical loss rates are unaffected by extra-vortex intrusions. Ozone-tracer correlations are then used to calculate ozone chemical loss rates. During the late winter the ozone chemical loss rate is found to be-46 q-6 (1•) ppbv/day. By mid-March 2000, the accumulated ozone chemical loss is 58 q-4 % in the lower stratosphere near 450 K potential temperature (-19 km altitude).
Arctic winter 2005: Implications for stratospheric ozone loss and climate change
Geophysical Research Letters, 2006
1] The Arctic polar vortex exhibited widespread regions of low temperatures during the winter of 2005, resulting in significant ozone depletion by chlorine and bromine species. We show that chemical loss of column ozone (DO 3 ) and the volume of Arctic vortex air cold enough to support the existence of polar stratospheric clouds (V PSC ) both exceed levels found for any other Arctic winter during the past 40 years. Cold conditions and ozone loss in the lowermost Arctic stratosphere (e.g., between potential temperatures of 360 to 400 K) were particularly unusual compared to previous years. Measurements indicate DO 3 = 121 ± 20 DU and that DO 3 versus V PSC lies along an extension of the compact, near linear relation observed for previous Arctic winters. The maximum value of V PSC during five to ten year intervals exhibits a steady, monotonic increase over the past four decades, indicating that the coldest Arctic winters have become significantly colder, and hence are more conducive to ozone depletion by anthropogenic halogens. Citation: Rex, M., et al. (2006), Arctic winter 2005: Implications for stratospheric ozone loss and climate change, Geophys. Res. Lett., 33, L23808,
Ozone depletion in and below the Arctic vortex for 1997
Geophysical Research Letters, 1998
The winter 1996/97 was quite unusual with late vortex formation and polar stratospheric cloud (PSC) development and subsequent record low temperatures in March. Ozone depletion in the Arctic vortex is determined using ozonesondes. The diabatic cooling is calculated with PV-theta mapped ozone mixing ratios and the large ozone depletions, especially at the center of the vortex where most PSC existence was predicted, enhances the diabatic cooling by up to 80%. The average vortex chemical ozone depletion from January 6 to April 6 is 33, 46, 46, 43, 35. 33. 32 and 21% in air masses ending at 375,400, 425, 450, 475. 500, 525, and 550 K (about 14 -22 km). This depletion is corrected for transport of ozone across the vortex edge calculated with reverse domain-filling trajectories. 375 K is in fact below the vortex, but the calculation method is applicable at this level with small changes. The column integrated chemical ozone depletion amounts to about 92 DU (21%), which is comparable to the depletions observed during the previous four winters.